package org.arclib.sound;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;

/**
 * Decode an OGG file to PCM data
 * 
 * @author Kevin Glass
 */
public class OggDecoder
{
	/** The conversion buffer size */
	private int convsize = 4096 * 4;
	/** The buffer used to read OGG file */
	private byte[] convbuffer = new byte[convsize]; // take 8k out of the data
													// segment, not the stack

	/**
	 * Create a new OGG decoder
	 */
	public OggDecoder()
	{
	}

	/**
	 * Get the data out of an OGG file
	 * 
	 * @param input
	 *            The input stream from which to read the OGG file
	 * @return The data describing the OGG thats been read
	 * @throws IOException
	 *             Indicaites a failure to read the OGG file
	 */
	public OggData getData(InputStream input) throws IOException
	{
		if (input == null)
		{
			throw new IOException("Failed to read OGG, source does not exist?");
		}
		ByteArrayOutputStream dataout = new ByteArrayOutputStream();

		// SyncState oy = new SyncState(); // sync and verify incoming physical
		// bitstream
		// StreamState os = new StreamState(); // take physical pages, weld into
		// a logical stream of packets
		// Page og = new Page(); // one Ogg bitstream page. Vorbis packets are
		// inside
		// Packet op = new Packet(); // one raw packet of data for decode
		//
		// Info vi = new Info(); // struct that stores all the static vorbis
		// bitstream settings
		// Comment vc = new Comment(); // struct that stores all the bitstream
		// user comments
		// DspState vd = new DspState(); // central working state for the
		// packet->PCM decoder
		// Block vb = new Block(vd); // local working space for packet->PCM
		// decode
		//
		// byte[] buffer;
		// int bytes = 0;
		//
		// boolean bigEndian =
		// ByteOrder.nativeOrder().equals(ByteOrder.BIG_ENDIAN);
		// // Decode setup
		//
		// oy.init(); // Now we can read pages
		//
		// while (true) { // we repeat if the bitstream is chained
		// int eos = 0;
		//
		// // grab some data at the head of the stream. We want the first page
		// // (which is guaranteed to be small and only contain the Vorbis
		// // stream initial header) We need the first page to get the stream
		// // serialno.
		//
		// // submit a 4k block to libvorbis' Ogg layer
		// int index = oy.buffer(4096);
		//			
		// buffer = oy.data;
		// try {
		// bytes = input.read(buffer, index, 4096);
		// } catch (Exception e) {
		// Log.error("Failure reading in vorbis");
		// Log.error(e);
		// System.exit(0);
		// }
		// oy.wrote(bytes);
		//
		// // Get the first page.
		// if (oy.pageout(og) != 1) {
		// // have we simply run out of data? If so, we're done.
		// if (bytes < 4096)
		// break;
		//
		// // error case. Must not be Vorbis data
		// Log.error("Input does not appear to be an Ogg bitstream.");
		// System.exit(0);
		// }
		//
		// // Get the serial number and set up the rest of decode.
		// // serialno first; use it to set up a logical stream
		// os.init(og.serialno());
		//
		// // extract the initial header from the first page and verify that the
		// // Ogg bitstream is in fact Vorbis data
		//
		// // I handle the initial header first instead of just having the code
		// // read all three Vorbis headers at once because reading the initial
		// // header is an easy way to identify a Vorbis bitstream and it's
		// // useful to see that functionality seperated out.
		//
		// vi.init();
		// vc.init();
		// if (os.pagein(og) < 0) {
		// // error; stream version mismatch perhaps
		// Log.error("Error reading first page of Ogg bitstream data.");
		// System.exit(0);
		// }
		//
		// if (os.packetout(op) != 1) {
		// // no page? must not be vorbis
		// Log.error("Error reading initial header packet.");
		// System.exit(0);
		// }
		//
		// if (vi.synthesis_headerin(vc, op) < 0) {
		// // error case; not a vorbis header
		// Log.error("This Ogg bitstream does not contain Vorbis audio data.");
		// System.exit(0);
		// }
		//
		// // At this point, we're sure we're Vorbis. We've set up the logical
		// // (Ogg) bitstream decoder. Get the comment and codebook headers and
		// // set up the Vorbis decoder
		//
		// // The next two packets in order are the comment and codebook
		// headers.
		// // They're likely large and may span multiple pages. Thus we reead
		// // and submit data until we get our two pacakets, watching that no
		// // pages are missing. If a page is missing, error out; losing a
		// // header page is the only place where missing data is fatal. */
		//
		// int i = 0;
		// while (i < 2) {
		// while (i < 2) {
		//
		// int result = oy.pageout(og);
		// if (result == 0)
		// break; // Need more data
		// // Don't complain about missing or corrupt data yet. We'll
		// // catch it at the packet output phase
		//
		// if (result == 1) {
		// os.pagein(og); // we can ignore any errors here
		// // as they'll also become apparent
		// // at packetout
		// while (i < 2) {
		// result = os.packetout(op);
		// if (result == 0)
		// break;
		// if (result == -1) {
		// // Uh oh; data at some point was corrupted or missing!
		// // We can't tolerate that in a header. Die.
		// Log.error("Corrupt secondary header.  Exiting.");
		// System.exit(0);
		// }
		// vi.synthesis_headerin(vc, op);
		// i++;
		// }
		// }
		// }
		// // no harm in not checking before adding more
		// index = oy.buffer(4096);
		// buffer = oy.data;
		// try {
		// bytes = input.read(buffer, index, 4096);
		// } catch (Exception e) {
		// Log.error("Failed to read Vorbis: ");
		// Log.error(e);
		// System.exit(0);
		// }
		// if (bytes == 0 && i < 2) {
		// Log.error("End of file before finding all Vorbis headers!");
		// System.exit(0);
		// }
		// oy.wrote(bytes);
		// }
		//
		// convsize = 4096 / vi.channels;
		//
		// // OK, got and parsed all three headers. Initialize the Vorbis
		// // packet->PCM decoder.
		// vd.synthesis_init(vi); // central decode state
		// vb.init(vd); // local state for most of the decode
		// // so multiple block decodes can
		// // proceed in parallel. We could init
		// // multiple vorbis_block structures
		// // for vd here
		//
		// float[][][] _pcm = new float[1][][];
		// int[] _index = new int[vi.channels];
		// // The rest is just a straight decode loop until end of stream
		// while (eos == 0) {
		// while (eos == 0) {
		//
		// int result = oy.pageout(og);
		// if (result == 0)
		// break; // need more data
		// if (result == -1) { // missing or corrupt data at this page position
		// Log.error("Corrupt or missing data in bitstream; continuing...");
		// } else {
		// os.pagein(og); // can safely ignore errors at
		// // this point
		// while (true) {
		// result = os.packetout(op);
		//
		// if (result == 0)
		// break; // need more data
		// if (result == -1) { // missing or corrupt data at this page position
		// // no reason to complain; already complained above
		// } else {
		// // we have a packet. Decode it
		// int samples;
		// if (vb.synthesis(op) == 0) { // test for success!
		// vd.synthesis_blockin(vb);
		// }
		//
		// // **pcm is a multichannel float vector. In stereo, for
		// // example, pcm[0] is left, and pcm[1] is right. samples is
		// // the size of each channel. Convert the float values
		// // (-1.<=range<=1.) to whatever PCM format and write it out
		//
		// while ((samples = vd.synthesis_pcmout(_pcm,
		// _index)) > 0) {
		// float[][] pcm = _pcm[0];
		// //boolean clipflag = false;
		// int bout = (samples < convsize ? samples
		// : convsize);
		//
		// // convert floats to 16 bit signed ints (host order) and
		// // interleave
		// for (i = 0; i < vi.channels; i++) {
		// int ptr = i * 2;
		// //int ptr=i;
		// int mono = _index[i];
		// for (int j = 0; j < bout; j++) {
		// int val = (int) (pcm[i][mono + j] * 32767.);
		// // short val=(short)(pcm[i][mono+j]*32767.);
		// // int val=(int)Math.round(pcm[i][mono+j]*32767.);
		// // might as well guard against clipping
		// if (val > 32767) {
		// val = 32767;
		// //clipflag = true;
		// }
		// if (val < -32768) {
		// val = -32768;
		// //clipflag = true;
		// }
		// if (val < 0)
		// val = val | 0x8000;
		//				
		// if (bigEndian) {
		// convbuffer[ptr] = (byte) (val >>> 8);
		// convbuffer[ptr + 1] = (byte) (val);
		// } else {
		// convbuffer[ptr] = (byte) (val);
		// convbuffer[ptr + 1] = (byte) (val >>> 8);
		// }
		// ptr += 2 * (vi.channels);
		// }
		// }
		//
		// dataout.write(convbuffer, 0, 2 * vi.channels * bout);
		//
		// vd.synthesis_read(bout); // tell libvorbis how
		// // many samples we
		// // actually consumed
		// }
		// }
		// }
		// if (og.eos() != 0)
		// eos = 1;
		// }
		// }
		// if (eos == 0) {
		// index = oy.buffer(4096);
		// if (index >= 0) {
		// buffer = oy.data;
		// try {
		// bytes = input.read(buffer, index, 4096);
		// } catch (Exception e) {
		// Log.error("Failure during vorbis decoding");
		// Log.error(e);
		// return null;
		// }
		// } else {
		// bytes = 0;
		// }
		// oy.wrote(bytes);
		// if (bytes == 0)
		// eos = 1;
		// }
		// }
		//
		// // clean up this logical bitstream; before exit we see if we're
		// // followed by another [chained]
		//
		// os.clear();
		//
		// // ogg_page and ogg_packet structs always point to storage in
		// // libvorbis. They're never freed or manipulated directly
		//
		// vb.clear();
		// vd.clear();
		// vi.clear(); // must be called last
		// }
		//
		// // OK, clean up the framer
		// oy.clear();
		// OggData ogg = new OggData();
		// ogg.channels = vi.channels;
		// ogg.rate = vi.rate;

		OggInputStream oggInput = new OggInputStream(input);

		boolean done = false;
		while (!oggInput.atEnd())
		{
			dataout.write(oggInput.read());
		}

		OggData ogg = new OggData();
		ogg.channels = oggInput.getChannels();
		ogg.rate = oggInput.getRate();

		byte[] data = dataout.toByteArray();
		ogg.data = ByteBuffer.allocateDirect(data.length);
		ogg.data.put(data);
		ogg.data.rewind();

		return ogg;
	}
}
